Biochemical evidence for multiple I-E Ia molecules.
Sequential immunoprecipitation and isoelectric focusing analyses with monoclonal I-E-specific antibodies presented in this paper indicate the existence of multiple I-E molecules. In sequential immunoprecipitations with 13-4 (anti-Ia.7) and 17-3-3 (anti-Ia.22) monoclonal antibodies, 17-3-3 only partially cleared I-E molecules immunoprecipitated by 13-4. Similarly, 13-4 monoclonal antibody only partially cleared I-E molecules precipitated by 17-3-3 monoclonal antibody. These results suggested a minimum of three I-E molecules. One I-E molecule expresses both 13-4 and 17-3-3 determinants, a second I-E molecule expresses only 17-3-3 determinants, and a third I-E molecule expresses only 13-4 determinants. Isoelectric focusing analyses of I-E molecules immunoprecipitated by 13-4 and 17-3-3 showed differences in both Ae beta polypeptide chains and E alpha polypeptide chains. The sequential immunoprecipitation and isoelectric focusing analyses presented in this paper can be explained by a model in which there are at least two separate Ae genes being encoded within the I-A subregion and two separate E alpha genes being encoded within the I-E subregion. The 17-3-3 monoclonal antibody would recognize a determinant on only one of two Ae beta polypeptide chains and the 13-4 monoclonal antibody would recognize a determinant on only one of two E alpha polypeptide chains.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology*; D007525:Isoelectric Focusing; D051379:Mice; D010455:Peptides
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D010455:Peptides